I have few words in the range B2:B102. I have few more words in the
range I2:I10002. What I want to do is, compare the first word in the
range B2:B102 (B2.value) with first word in the range I2:I10002
(I2.value) and count how many characters (letters) are common and save
the count in the range C2.

Now compare B2 with I3 and list the count in C3. Go on comparing till
B2 with I10002 and list the count in C10002. Once this is finished,
move to second word in the range B2:B102 (B3.value).

Compare B3 with I2 and check the count. Now if this greater than the
value in cell C2, then update C2 with then new count else leave
C2.value as it is.